一、MTK6580 平台 Camera 驱动整体框架

mtk平台三大件调试中，camera的调试难度最大，问题也就最多，为此特地分析了一下整个camera驱动

部分实现过程，以下为camera驱动框架序列图：

      

从图中可以看出，整个框架分为三个部分hal部分逻辑调用，kernel层的通用驱动sensorlist.c 和具体IC的

驱动xxxx_mipi_raw.c，kernel起来后不会直接去访问硬件sensor,而是会注册相关的驱动，之后Android系

统起来后会启动相关的服务如：camera_service，在camera服务中会直接去访问hal,kernel驱动，进而操

作camera为此本文也穿插了部分hal层的调用,至于camera_service后面章节会继续补充。

二、 Camera 驱动的具体实现

========================HAL 层部分初始调用========================
文件：vendor/mediatek/proprietary/hardware/mtkcam/common/module_hal/devicemgr/CamDeviceManagerBase.cpp

<code class=" hljs " style="border-radius: 3px; padding: 0.5em; font-family: Monaco, Menlo, Consolas, 'Courier New', monospace; font-size: 12px; color: rgb(248, 248, 242); border: 0px; display: block; overflow-x: auto; background: rgb(35, 36, 31);">int32_t
CamDeviceManagerBase::
getNumberOfDevices()
{...mi4DeviceNum = enumDeviceLocked();...
}</code>

文件：vendor/mediatek/proprietary/hardware/mtkcam/legacy/platform/mt6580/devicemgr/CamDeviceManagerImp.cpp

<code class=" hljs " style="border-radius: 3px; padding: 0.5em; font-family: Monaco, Menlo, Consolas, 'Courier New', monospace; font-size: 12px; color: rgb(248, 248, 242); border: 0px; display: block; overflow-x: auto; background: rgb(35, 36, 31);">int32_t
CamDeviceManagerImp::
enumDeviceLocked()
{...
<span class="hljs-comment" style="border-radius: 0px !important; color: rgb(117, 113, 94);">//------------------------------------------------------------------------------</span>
<span class="hljs-preprocessor" style="border-radius: 0px !important;">#if '1'==MTKCAM_HAVE_SENSOR_HAL</span><span class="hljs-comment" style="border-radius: 0px !important; color: rgb(117, 113, 94);">//</span>IHalSensorList*<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">const</span> pHalSensorList = IHalSensorList::get();size_t <span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">const</span> sensorNum = pHalSensorList->searchSensors();
<span class="hljs-preprocessor" style="border-radius: 0px !important;">#endif</span>...<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">return</span>  i4DeviceNum;
}</code>

文件：vendor/mediatek/proprietary/hardware/mtkcam/legacy/platform/mt6580/hal/sensor/HalSensorList.cpp

<code class=" hljs " style="border-radius: 3px; padding: 0.5em; font-family: Monaco, Menlo, Consolas, 'Courier New', monospace; font-size: 12px; color: rgb(248, 248, 242); border: 0px; display: block; overflow-x: auto; background: rgb(35, 36, 31);">MUINT
HalSensorList::
searchSensors()
{Mutex::Autolock _l(mEnumSensorMutex);<span class="hljs-comment" style="border-radius: 0px !important; color: rgb(117, 113, 94);">//</span>MY_LOGD(<span class="hljs-string" style="border-radius: 0px !important; color: rgb(230, 219, 116);">"searchSensors"</span>);<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">return</span>  enumerateSensor_Locked();
}</code>

文件：vendor/mediatek/proprietary/hardware/mtkcam/legacy/platform/mt6580/hal/sensor/HalSensorList.enumList.cpp

<code class=" hljs " style="border-radius: 3px; padding: 0.5em; font-family: Monaco, Menlo, Consolas, 'Courier New', monospace; font-size: 12px; color: rgb(248, 248, 242); border: 0px; display: block; overflow-x: auto; background: rgb(35, 36, 31);">MUINT
HalSensorList::
enumerateSensor_Locked()
{....MUINT halSensorDev = SENSOR_DEV_NONE;NSFeature::SensorInfoBase* pSensorInfo ;SensorDrv *<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">const</span> pSensorDrv = SensorDrv::get();SeninfDrv *<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">const</span> pSeninfDrv = SeninfDrv::createInstance();<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">int</span> <span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">const</span> iSensorsList = pSensorDrv->impSearchSensor(NULL);....
}</code>

文件：vendor/mediatek/proprietary/hardware/mtkcam/legacy/platform/mt6580/hal/sensor/imgsensor_drv.cpp

<code class=" hljs " style="border-radius: 3px; padding: 0.5em; font-family: Monaco, Menlo, Consolas, 'Courier New', monospace; font-size: 12px; color: rgb(248, 248, 242); border: 0px; display: block; overflow-x: auto; background: rgb(35, 36, 31);">MINT32
ImgSensorDrv::impSearchSensor(pfExIdChk pExIdChkCbf)
{....GetSensorInitFuncList(&m_pstSensorInitFunc);LOG_MSG(<span class="hljs-string" style="border-radius: 0px !important; color: rgb(230, 219, 116);">"SENSOR search start \n"</span>);<span class="hljs-built_in" style="border-radius: 0px !important; color: rgb(230, 219, 116);">sprintf</span>(cBuf,<span class="hljs-string" style="border-radius: 0px !important; color: rgb(230, 219, 116);">"/dev/%s"</span>,CAMERA_HW_DEVNAME);m_fdSensor = ::open(cBuf, O_RDWR);......<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">for</span> (i = <span class="hljs-number" style="border-radius: 0px !important; color: rgb(174, 129, 255);">0</span>; i < MAX_NUM_OF_SUPPORT_SENSOR; i++) {....err = ioctl(m_fdSensor, KDIMGSENSORIOC_X_SET_DRIVER,&id[KDIMGSENSOR_INVOKE_DRIVER_0] );...err = ioctl(m_fdSensor, KDIMGSENSORIOC_T_CHECK_IS_ALIVE);......
}</code>

GetSensorInitFuncList的实现
文件：vendor/mediatek/proprietary/custom/mt6580/hal/imgsensor_src/sensorlist.cpp

<code class=" hljs " style="border-radius: 3px; padding: 0.5em; font-family: Monaco, Menlo, Consolas, 'Courier New', monospace; font-size: 12px; color: rgb(248, 248, 242); border: 0px; display: block; overflow-x: auto; background: rgb(35, 36, 31);">UINT32 GetSensorInitFuncList(MSDK_SENSOR_INIT_FUNCTION_STRUCT **ppSensorList)
{<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">if</span> (NULL == ppSensorList) {ALOGE(<span class="hljs-string" style="border-radius: 0px !important; color: rgb(230, 219, 116);">"ERROR: NULL pSensorList\n"</span>);<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">return</span> MHAL_UNKNOWN_ERROR;}*ppSensorList = &SensorList[<span class="hljs-number" style="border-radius: 0px !important; color: rgb(174, 129, 255);">0</span>];<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">return</span> MHAL_NO_ERROR;
} </code>

Sensor 列表的定义如下：

<code class=" hljs " style="border-radius: 3px; padding: 0.5em; font-family: Monaco, Menlo, Consolas, 'Courier New', monospace; font-size: 12px; color: rgb(248, 248, 242); border: 0px; display: block; overflow-x: auto; background: rgb(35, 36, 31);">MSDK_SENSOR_INIT_FUNCTION_STRUCT SensorList[] =
{
<span class="hljs-comment" style="border-radius: 0px !important; color: rgb(117, 113, 94);">//xc add camera start</span>
<span class="hljs-preprocessor" style="border-radius: 0px !important;">#if defined(GC2365MIPI_RAW)</span>RAW_INFO(GC2365MIPI_SENSOR_ID, SENSOR_DRVNAME_GC2365MIPI_RAW, NULL),
<span class="hljs-preprocessor" style="border-radius: 0px !important;">#endif</span><span class="hljs-preprocessor" style="border-radius: 0px !important;">#if defined(GC2355_MIPI_RAW_BAIKANG_M8112)</span>RAW_INFO(GC2355_SENSOR_ID, SENSOR_DRVNAME_GC2355_MIPI_RAW,NULL),
<span class="hljs-preprocessor" style="border-radius: 0px !important;">#endif</span>
....
}</code>

获取sensor列表后，紧接着通过：
err = ioctl(m_fdSensor, KDIMGSENSORIOC_X_SET_DRIVER,&id[KDIMGSENSOR_INVOKE_DRIVER_0] );
err = ioctl(m_fdSensor, KDIMGSENSORIOC_T_CHECK_IS_ALIVE);
访问kernel层的数据
====================== Kernel 层驱动的实现 ========================
1. 针对前后摄注册platform 设备和驱动
文件：kernel-3.18/drivers/misc/mediatek/imgsensor/src/mt6580/kd_sensorlist.c

<code class=" hljs " style="border-radius: 3px; padding: 0.5em; font-family: Monaco, Menlo, Consolas, 'Courier New', monospace; font-size: 12px; color: rgb(248, 248, 242); border: 0px; display: block; overflow-x: auto; background: rgb(35, 36, 31);"><span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">static</span> <span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">int</span> __init CAMERA_HW_i2C_init(<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">void</span>)
{....<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">if</span> (platform_driver_register(&g_stCAMERA_HW_Driver)) <span class="hljs-comment" style="border-radius: 0px !important; color: rgb(117, 113, 94);">//注册主摄platform 驱动</span><span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">if</span> (platform_driver_register(&g_stCAMERA_HW_Driver2)) <span class="hljs-comment" style="border-radius: 0px !important; color: rgb(117, 113, 94);">//注册副摄platform 驱动</span>....<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">return</span> <span class="hljs-number" style="border-radius: 0px !important; color: rgb(174, 129, 255);">0</span>;
}</code>

主摄平台驱动的定义：

<code class=" hljs " style="border-radius: 3px; padding: 0.5em; font-family: Monaco, Menlo, Consolas, 'Courier New', monospace; font-size: 12px; color: rgb(248, 248, 242); border: 0px; display: block; overflow-x: auto; background: rgb(35, 36, 31);"><span class="hljs-preprocessor" style="border-radius: 0px !important;">#ifdef CONFIG_OF</span>
<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">static</span> <span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">const</span> <span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">struct</span> of_device_id CAMERA_HW_of_ids[] = {{.compatible = <span class="hljs-string" style="border-radius: 0px !important; color: rgb(230, 219, 116);">"mediatek,camera_hw"</span>,},  <span class="hljs-comment" style="border-radius: 0px !important; color: rgb(117, 113, 94);">//主摄匹配规则</span>{}
};
<span class="hljs-preprocessor" style="border-radius: 0px !important;">#endif</span><span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">static</span> <span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">struct</span> platform_driver g_stCAMERA_HW_Driver = {.probe = CAMERA_HW_probe,.remove = CAMERA_HW_remove,.suspend = CAMERA_HW_suspend,.resume = CAMERA_HW_resume,.driver = {.name = <span class="hljs-string" style="border-radius: 0px !important; color: rgb(230, 219, 116);">"image_sensor"</span>,.owner = THIS_MODULE,
<span class="hljs-preprocessor" style="border-radius: 0px !important;">#ifdef CONFIG_OF</span>.of_match_table = CAMERA_HW_of_ids,
<span class="hljs-preprocessor" style="border-radius: 0px !important;">#endif</span>}
};</code>

副摄平台驱动的定义：

<code class=" hljs " style="border-radius: 3px; padding: 0.5em; font-family: Monaco, Menlo, Consolas, 'Courier New', monospace; font-size: 12px; color: rgb(248, 248, 242); border: 0px; display: block; overflow-x: auto; background: rgb(35, 36, 31);"><span class="hljs-preprocessor" style="border-radius: 0px !important;">#ifdef CONFIG_OF</span>
<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">static</span> <span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">const</span> <span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">struct</span> of_device_id CAMERA_HW2_of_ids[] = {{.compatible = <span class="hljs-string" style="border-radius: 0px !important; color: rgb(230, 219, 116);">"mediatek,camera_hw2"</span>,},<span class="hljs-comment" style="border-radius: 0px !important; color: rgb(117, 113, 94);">//副摄匹配规则</span>{}
};
<span class="hljs-preprocessor" style="border-radius: 0px !important;">#endif</span><span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">static</span> <span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">struct</span> platform_driver g_stCAMERA_HW_Driver2 = {.probe = CAMERA_HW_probe2,.remove = CAMERA_HW_remove2,.suspend = CAMERA_HW_suspend2,.resume = CAMERA_HW_resume2,.driver = {.name = <span class="hljs-string" style="border-radius: 0px !important; color: rgb(230, 219, 116);">"image_sensor_bus2"</span>,.owner = THIS_MODULE,
<span class="hljs-preprocessor" style="border-radius: 0px !important;">#ifdef CONFIG_OF</span>.of_match_table = CAMERA_HW2_of_ids,
<span class="hljs-preprocessor" style="border-radius: 0px !important;">#endif</span>}
};</code>

主副摄cam在dts中定义设备信息：

<code class=" hljs " style="border-radius: 3px; padding: 0.5em; font-family: Monaco, Menlo, Consolas, 'Courier New', monospace; font-size: 12px; color: rgb(248, 248, 242); border: 0px; display: block; overflow-x: auto; background: rgb(35, 36, 31);">kd_camera_hw1:kd_camera_hw1@<span class="hljs-number" style="border-radius: 0px !important; color: rgb(174, 129, 255);">15008000</span> {compatible = <span class="hljs-string" style="border-radius: 0px !important; color: rgb(230, 219, 116);">"mediatek,camera_hw"</span>; <span class="hljs-comment" style="border-radius: 0px !important; color: rgb(117, 113, 94);">//这里必须和主摄一致</span>reg = <<span class="hljs-number" style="border-radius: 0px !important; color: rgb(174, 129, 255);">0x15008000</span> <span class="hljs-number" style="border-radius: 0px !important; color: rgb(174, 129, 255);">0x1000</span>>;  <span class="hljs-comment" style="border-radius: 0px !important; color: rgb(117, 113, 94);">/* SENINF_ADDR */</span>vcama-supply = <&mt_pmic_vcama_ldo_reg>;vcamd-supply = <&mt_pmic_vcamd_ldo_reg>;vcamaf-supply = <&mt_pmic_vcamaf_ldo_reg>;vcamio-supply = <&mt_pmic_vcamio_ldo_reg>;};
kd_camera_hw2:kd_camera_hw2@<span class="hljs-number" style="border-radius: 0px !important; color: rgb(174, 129, 255);">15008000</span> {compatible = <span class="hljs-string" style="border-radius: 0px !important; color: rgb(230, 219, 116);">"mediatek,camera_hw2"</span>; <span class="hljs-comment" style="border-radius: 0px !important; color: rgb(117, 113, 94);">//这里必须和副摄一致</span>reg = <<span class="hljs-number" style="border-radius: 0px !important; color: rgb(174, 129, 255);">0x15008000</span> <span class="hljs-number" style="border-radius: 0px !important; color: rgb(174, 129, 255);">0x1000</span>>;  <span class="hljs-comment" style="border-radius: 0px !important; color: rgb(117, 113, 94);">/* SENINF_ADDR */</span>
};</code>

       当内核启动后，会解析dts编译生成的dtb文件，注册里面定义的device,如果和驱动中定义id一致，

则挂载启动。上面注册了两个platform 驱动g_stCAMERA_HW_Driver，g_stCAMERA_HW_Driver2，

如果匹配成功会调用各自的probe函数CAMERA_HW_probe，CAMERA_HW_probe2

2. 平台probe 函数的实现
主摄probe，CAMERA_HW_probe的实现如下：

<code class=" hljs " style="border-radius: 3px; padding: 0.5em; font-family: Monaco, Menlo, Consolas, 'Courier New', monospace; font-size: 12px; color: rgb(248, 248, 242); border: 0px; display: block; overflow-x: auto; background: rgb(35, 36, 31);"><span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">static</span> <span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">int</span> CAMERA_HW_probe(<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">struct</span> platform_device *pdev)
{
<span class="hljs-preprocessor" style="border-radius: 0px !important;">#if !defined(CONFIG_MTK_LEGACY)</span>mtkcam_gpio_init(pdev);mtkcam_pin_mux_init(pdev);
<span class="hljs-preprocessor" style="border-radius: 0px !important;">#endif</span><span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">return</span> i2c_add_driver(&CAMERA_HW_i2c_driver);
}</code>

副摄probe，CAMERA_HW_probe的实现如下：

<code class=" hljs " style="border-radius: 3px; padding: 0.5em; font-family: Monaco, Menlo, Consolas, 'Courier New', monospace; font-size: 12px; color: rgb(248, 248, 242); border: 0px; display: block; overflow-x: auto; background: rgb(35, 36, 31);"><span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">static</span> <span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">int</span> CAMERA_HW_probe2(<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">struct</span> platform_device *pdev)
{<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">return</span> i2c_add_driver(&CAMERA_HW_i2c_driver2);
}</code>

从上可以看出在main/sub 的平台probe中分别注册了各自的i2c驱动CAMERA_HW_i2c_driver，
CAMERA_HW_i2c_driver2， main sensor 的CAMERA_HW_i2c_driver定义如下：

<code class=" hljs " style="border-radius: 3px; padding: 0.5em; font-family: Monaco, Menlo, Consolas, 'Courier New', monospace; font-size: 12px; color: rgb(248, 248, 242); border: 0px; display: block; overflow-x: auto; background: rgb(35, 36, 31);"><span class="hljs-preprocessor" style="border-radius: 0px !important;">#ifdef CONFIG_OF</span>
<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">static</span> <span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">const</span> <span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">struct</span> of_device_id CAMERA_HW_i2c_of_ids[] = {{ .compatible = <span class="hljs-string" style="border-radius: 0px !important; color: rgb(230, 219, 116);">"mediatek,camera_main"</span>, },{}
};
<span class="hljs-preprocessor" style="border-radius: 0px !important;">#endif</span><span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">struct</span> i2c_driver CAMERA_HW_i2c_driver = {.probe = CAMERA_HW_i2c_probe,.remove = CAMERA_HW_i2c_remove,.driver = {.name = CAMERA_HW_DRVNAME1,.owner = THIS_MODULE,<span class="hljs-preprocessor" style="border-radius: 0px !important;">#ifdef CONFIG_OF</span>.of_match_table = CAMERA_HW_i2c_of_ids,
<span class="hljs-preprocessor" style="border-radius: 0px !important;">#endif</span>},.id_table = CAMERA_HW_i2c_id,
};
sub sensor 的CAMERA_HW_i2c_driver定义如下：
<span class="hljs-preprocessor" style="border-radius: 0px !important;">#ifdef CONFIG_OF</span><span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">static</span> <span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">const</span> <span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">struct</span> of_device_id CAMERA_HW2_i2c_driver_of_ids[] = {{ .compatible = <span class="hljs-string" style="border-radius: 0px !important; color: rgb(230, 219, 116);">"mediatek,camera_sub"</span>, },{}};
<span class="hljs-preprocessor" style="border-radius: 0px !important;">#endif</span><span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">struct</span> i2c_driver CAMERA_HW_i2c_driver2 = {.probe = CAMERA_HW_i2c_probe2,.remove = CAMERA_HW_i2c_remove2,.driver = {.name = CAMERA_HW_DRVNAME2,.owner = THIS_MODULE,
<span class="hljs-preprocessor" style="border-radius: 0px !important;">#ifdef CONFIG_OF</span>.of_match_table = CAMERA_HW2_i2c_driver_of_ids,
<span class="hljs-preprocessor" style="border-radius: 0px !important;">#endif</span>},.id_table = CAMERA_HW_i2c_id2,
};</code>

对应main/sub camera i2c 设备dts定义如下
文件：kernel-3.18/arch/arm/boot/dts/cust_i2c.dtsi

<code class=" hljs " style="border-radius: 3px; padding: 0.5em; font-family: Monaco, Menlo, Consolas, 'Courier New', monospace; font-size: 12px; color: rgb(248, 248, 242); border: 0px; display: block; overflow-x: auto; background: rgb(35, 36, 31);">&i2c0 {camera_main@<span class="hljs-number" style="border-radius: 0px !important; color: rgb(174, 129, 255);">10</span> {compatible = <span class="hljs-string" style="border-radius: 0px !important; color: rgb(230, 219, 116);">"mediatek,camera_main"</span>; <span class="hljs-comment" style="border-radius: 0px !important; color: rgb(117, 113, 94);">//和 CAMERA_HW_i2c_driver定义的一致</span>reg = <<span class="hljs-number" style="border-radius: 0px !important; color: rgb(174, 129, 255);">0x10</span>>;};camera_main_af@<span class="hljs-number" style="border-radius: 0px !important; color: rgb(174, 129, 255);">0</span>c {compatible = <span class="hljs-string" style="border-radius: 0px !important; color: rgb(230, 219, 116);">"mediatek,camera_main_af"</span>;reg = <<span class="hljs-number" style="border-radius: 0px !important; color: rgb(174, 129, 255);">0x0c</span>>;};camera_sub@<span class="hljs-number" style="border-radius: 0px !important; color: rgb(174, 129, 255);">3</span>c {compatible = <span class="hljs-string" style="border-radius: 0px !important; color: rgb(230, 219, 116);">"mediatek,camera_sub"</span>; <span class="hljs-comment" style="border-radius: 0px !important; color: rgb(117, 113, 94);">//和CAMERA_HW_i2c_driver2定义的一致</span>reg = <<span class="hljs-number" style="border-radius: 0px !important; color: rgb(174, 129, 255);">0x3c</span>>;};};</code>

3. I2c probe的实现
从上可以看出main/sub sensor在各自的平台probe中，注册了i2c_driver,当各自的i2c_driver 和设备
匹配（如何匹配本章不作分析）成功后，会调用各自的i2c_probe函数。 main sensor  的probe函数
CAMERA_HW_i2c_probe：

<code class=" hljs " style="border-radius: 3px; padding: 0.5em; font-family: Monaco, Menlo, Consolas, 'Courier New', monospace; font-size: 12px; color: rgb(248, 248, 242); border: 0px; display: block; overflow-x: auto; background: rgb(35, 36, 31);"><span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">static</span> <span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">int</span> CAMERA_HW_i2c_probe(<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">struct</span> i2c_client *client, <span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">const</span> <span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">struct</span> i2c_device_id *id)
{.....<span class="hljs-comment" style="border-radius: 0px !important; color: rgb(117, 113, 94);">/* Register char driver */</span>i4RetValue = RegisterCAMERA_HWCharDrv();.....<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">return</span> <span class="hljs-number" style="border-radius: 0px !important; color: rgb(174, 129, 255);">0</span>;
}</code>

sub sensor 的probe函数CAMERA_HW_i2c_probe2：

<code class=" hljs " style="border-radius: 3px; padding: 0.5em; font-family: Monaco, Menlo, Consolas, 'Courier New', monospace; font-size: 12px; color: rgb(248, 248, 242); border: 0px; display: block; overflow-x: auto; background: rgb(35, 36, 31);"><span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">static</span> <span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">int</span> CAMERA_HW_i2c_probe2(<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">struct</span> i2c_client *client, <span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">const</span> <span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">struct</span> i2c_device_id *id)
{.....<span class="hljs-comment" style="border-radius: 0px !important; color: rgb(117, 113, 94);">/* Register char driver */</span>i4RetValue = RegisterCAMERA_HWCharDrv2();.....
}</code>

从上可以看出main/sub 在各自的i2cprobe中，通过该调用RegisterCAMERA_HWCharDrv，RegisterCAMERA_HWCharDrv2 注册了字符设备。 各自注册cdev函数实现如下：

<code class=" hljs " style="border-radius: 3px; padding: 0.5em; font-family: Monaco, Menlo, Consolas, 'Courier New', monospace; font-size: 12px; color: rgb(248, 248, 242); border: 0px; display: block; overflow-x: auto; background: rgb(35, 36, 31);"><span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">static</span> <span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">inline</span> <span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">int</span> RegisterCAMERA_HWCharDrv(<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">void</span>)<span class="hljs-comment" style="border-radius: 0px !important; color: rgb(117, 113, 94);">//main sensor 注册cdev</span>
{.....<span class="hljs-comment" style="border-radius: 0px !important; color: rgb(117, 113, 94);">/* Attatch file operation. */</span>cdev_init(g_pCAMERA_HW_CharDrv, &g_stCAMERA_HW_fops); <span class="hljs-comment" style="border-radius: 0px !important; color: rgb(117, 113, 94);">//初始化字符设备</span><span class="hljs-comment" style="border-radius: 0px !important; color: rgb(117, 113, 94);">/* Add to system */</span>cdev_add(g_pCAMERA_HW_CharDrv, g_CAMERA_HWdevno, <span class="hljs-number" style="border-radius: 0px !important; color: rgb(174, 129, 255);">1</span>) <span class="hljs-comment" style="border-radius: 0px !important; color: rgb(117, 113, 94);">//注册到内核</span><span class="hljs-comment" style="border-radius: 0px !important; color: rgb(117, 113, 94);">//创建目录 /sys/class/sensordrv/</span>sensor_class = class_create(THIS_MODULE, <span class="hljs-string" style="border-radius: 0px !important; color: rgb(230, 219, 116);">"sensordrv"</span>); <span class="hljs-comment" style="border-radius: 0px !important; color: rgb(117, 113, 94);">//创建目录/sys/class/sensordrv/kd_camera_hw </span>sensor_device = device_create(sensor_class, NULL, g_CAMERA_HWdevno, NULL, CAMERA_HW_DRVNAME1); ....	<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">return</span> <span class="hljs-number" style="border-radius: 0px !important; color: rgb(174, 129, 255);">0</span>;
}
<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">static</span> <span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">inline</span> <span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">int</span> RegisterCAMERA_HWCharDrv2(<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">void</span>)<span class="hljs-comment" style="border-radius: 0px !important; color: rgb(117, 113, 94);">//sub sensor 注册cdev</span>
{....<span class="hljs-comment" style="border-radius: 0px !important; color: rgb(117, 113, 94);">/* Attatch file operation. */</span>cdev_init(g_pCAMERA_HW_CharDrv2, &g_stCAMERA_HW_fops0);<span class="hljs-comment" style="border-radius: 0px !important; color: rgb(117, 113, 94);">//初始化字符设备 </span><span class="hljs-comment" style="border-radius: 0px !important; color: rgb(117, 113, 94);">/* Add to system */</span>cdev_add(g_pCAMERA_HW_CharDrv2, g_CAMERA_HWdevno2, <span class="hljs-number" style="border-radius: 0px !important; color: rgb(174, 129, 255);">1</span>));<span class="hljs-comment" style="border-radius: 0px !important; color: rgb(117, 113, 94);">//注册到内核</span><span class="hljs-comment" style="border-radius: 0px !important; color: rgb(117, 113, 94);">//创建目录 /sys/class/sensordrv2/</span>sensor2_class = class_create(THIS_MODULE, <span class="hljs-string" style="border-radius: 0px !important; color: rgb(230, 219, 116);">"sensordrv2"</span>);<span class="hljs-comment" style="border-radius: 0px !important; color: rgb(117, 113, 94);">//创建目录/sys/class/sensordrv2/kd_camera_hw_bus2</span>sensor_device2 = device_create(sensor2_class, NULL, g_CAMERA_HWdevno2, NULL, CAMERA_HW_DRVNAME2);....<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">return</span> <span class="hljs-number" style="border-radius: 0px !important; color: rgb(174, 129, 255);">0</span>;
}
main/sub 创建各自的字符设备过程中绑定各自的fops,g_stCAMERA_HW_fops和g_stCAMERA_HW_fops0
他们各自定义如下
<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">static</span> <span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">const</span> <span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">struct</span> file_operations g_stCAMERA_HW_fops = { <span class="hljs-comment" style="border-radius: 0px !important; color: rgb(117, 113, 94);">//main sensor fops</span>.owner = THIS_MODULE,.open = CAMERA_HW_Open,.release = CAMERA_HW_Release,.unlocked_ioctl = CAMERA_HW_Ioctl,
<span class="hljs-preprocessor" style="border-radius: 0px !important;">#ifdef CONFIG_COMPAT</span>.compat_ioctl = CAMERA_HW_Ioctl_Compat,
<span class="hljs-preprocessor" style="border-radius: 0px !important;">#endif</span>};<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">static</span> <span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">const</span> <span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">struct</span> file_operations g_stCAMERA_HW_fops0 = { <span class="hljs-comment" style="border-radius: 0px !important; color: rgb(117, 113, 94);">//sub sensor fops</span>.owner = THIS_MODULE,.open = CAMERA_HW_Open2,.release = CAMERA_HW_Release2,.unlocked_ioctl = CAMERA_HW_Ioctl,
<span class="hljs-preprocessor" style="border-radius: 0px !important;">#ifdef CONFIG_COMPAT</span>.compat_ioctl = CAMERA_HW_Ioctl_Compat,
<span class="hljs-preprocessor" style="border-radius: 0px !important;">#endif</span>};</code>

从上可以看出各自的fops指定了相同的Iioctl函数，意味着上层操作main/sub sensor  只需要对应一个
底层的ioctl即可，至于sensor的区分可以借助idx,后面会讲到

<code class=" hljs " style="border-radius: 3px; padding: 0.5em; font-family: Monaco, Menlo, Consolas, 'Courier New', monospace; font-size: 12px; color: rgb(248, 248, 242); border: 0px; display: block; overflow-x: auto; background: rgb(35, 36, 31);"><span class="hljs-comment" style="border-radius: 0px !important; color: rgb(117, 113, 94);">/*******************************************************************************
* CAMERA_HW_Ioctl
********************************************************************************/</span><span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">static</span> <span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">long</span> CAMERA_HW_Ioctl(<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">struct</span> file *a_pstFile,<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">unsigned</span> <span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">int</span> a_u4Command, <span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">unsigned</span> <span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">long</span> a_u4Param)
{...pIdx = (u32 *) pBuff;<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">switch</span> (a_u4Command) {...<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">case</span> KDIMGSENSORIOC_X_SET_DRIVER:i4RetValue = kdSetDriver((<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">unsigned</span> <span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">int</span> *)pBuff);<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">break</span>;<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">case</span> KDIMGSENSORIOC_X_FEATURECONCTROL:i4RetValue = adopt_CAMERA_HW_FeatureControl(pBuff);<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">break</span>;<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">case</span> KDIMGSENSORIOC_T_CHECK_IS_ALIVE:i4RetValue = adopt_CAMERA_HW_CheckIsAlive();<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">break</span>;....<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">default</span>:PK_DBG(<span class="hljs-string" style="border-radius: 0px !important; color: rgb(230, 219, 116);">"No such command\n"</span>);i4RetValue = -EPERM;<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">break</span>;}.....
}</code>

这里ioctl和上层一一对应，上层要控制caemra 只需要传入相应的cmd和data而已

=================== HAL 调用Kernel 层驱动的逻辑 ======================
       前面介绍了HAL层调用ioctl 和 kernel层注册驱动，接下来继续分析，HAL层调用 后驱动
具体的实现流程。
4. ioctl 底层的实现
4.1先来看ioctl(m_fdSensor, KDIMGSENSORIOC_X_SET_DRIVER,&id[KDIMGSENSOR_INVOKE_DRIVER_0] );
当KDIMGSENSORIOC_X_SET_DRIVER被传下时，会调用kernel层的kdSetDriver接口

<code class=" hljs " style="border-radius: 3px; padding: 0.5em; font-family: Monaco, Menlo, Consolas, 'Courier New', monospace; font-size: 12px; color: rgb(248, 248, 242); border: 0px; display: block; overflow-x: auto; background: rgb(35, 36, 31);"><span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">int</span> kdSetDriver(<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">unsigned</span> <span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">int</span> *pDrvIndex)
{...kdGetSensorInitFuncList(&pSensorList))   <span class="hljs-comment" style="border-radius: 0px !important; color: rgb(117, 113, 94);">//获得sensor初始化列表</span><span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">for</span> (i = KDIMGSENSOR_INVOKE_DRIVER_0; i < KDIMGSENSOR_MAX_INVOKE_DRIVERS; i++) {....pSensorList[drvIdx[i]].SensorInit(&g_pInvokeSensorFunc[i]); <span class="hljs-comment" style="border-radius: 0px !important; color: rgb(117, 113, 94);">//获取各个cam驱动中Init函数入口</span>....}<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">return</span> <span class="hljs-number" style="border-radius: 0px !important; color: rgb(174, 129, 255);">0</span>;
}</code>

kdGetSensorInitFuncList的实现：

<code class=" hljs " style="border-radius: 3px; padding: 0.5em; font-family: Monaco, Menlo, Consolas, 'Courier New', monospace; font-size: 12px; color: rgb(248, 248, 242); border: 0px; display: block; overflow-x: auto; background: rgb(35, 36, 31);">UINT32 kdGetSensorInitFuncList(ACDK_KD_SENSOR_INIT_FUNCTION_STRUCT **ppSensorList)
{<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">if</span> (NULL == ppSensorList) {PK_ERR(<span class="hljs-string" style="border-radius: 0px !important; color: rgb(230, 219, 116);">"[kdGetSensorInitFuncList]ERROR: NULL ppSensorList\n"</span>);<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">return</span> <span class="hljs-number" style="border-radius: 0px !important; color: rgb(174, 129, 255);">1</span>;}*ppSensorList = &kdSensorList[<span class="hljs-number" style="border-radius: 0px !important; color: rgb(174, 129, 255);">0</span>];  <span class="hljs-comment" style="border-radius: 0px !important; color: rgb(117, 113, 94);">//获取sensorlist数组首地址</span><span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">return</span> <span class="hljs-number" style="border-radius: 0px !important; color: rgb(174, 129, 255);">0</span>;
}				<span class="hljs-comment" style="border-radius: 0px !important; color: rgb(117, 113, 94);">/* kdGetSensorInitFuncList() */</span></code>

kdSensorList定义如下：
文件：kernel-3.18/drivers/misc/mediatek/imgsensor/src/mt6580/kd_sensorlist.h

<code class=" hljs " style="border-radius: 3px; padding: 0.5em; font-family: Monaco, Menlo, Consolas, 'Courier New', monospace; font-size: 12px; color: rgb(248, 248, 242); border: 0px; display: block; overflow-x: auto; background: rgb(35, 36, 31);">ACDK_KD_SENSOR_INIT_FUNCTION_STRUCT kdSensorList[MAX_NUM_OF_SUPPORT_SENSOR+<span class="hljs-number" style="border-radius: 0px !important; color: rgb(174, 129, 255);">1</span>] =
{....<span class="hljs-preprocessor" style="border-radius: 0px !important;">#if defined(SUB_GC2355_MIPI_RAW)</span>{GC2355S_SENSOR_ID, SENSOR_DRVNAME_GC2355S_MIPI_RAW,Sub_GC2355_MIPI_RAW_SensorInit},
<span class="hljs-preprocessor" style="border-radius: 0px !important;">#endif</span>....
}</code>

获取列表之后紧接着调用各自的Init函数,这里以GC2355为例

<code class=" hljs " style="border-radius: 3px; padding: 0.5em; font-family: Monaco, Menlo, Consolas, 'Courier New', monospace; font-size: 12px; color: rgb(248, 248, 242); border: 0px; display: block; overflow-x: auto; background: rgb(35, 36, 31);">UINT32 GC2235MIPI_RAW_SensorInit(PSENSOR_FUNCTION_STRUCT *pfFunc)
{<span class="hljs-comment" style="border-radius: 0px !important; color: rgb(117, 113, 94);">/* To Do : Check Sensor status here */</span><span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">if</span> (pfFunc!=NULL)*pfFunc=&sensor_func;<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">return</span> ERROR_NONE;
}	<span class="hljs-comment" style="border-radius: 0px !important; color: rgb(117, 113, 94);">/*	GC2235MIPI_RAW_SensorInit	*/</span></code>

丛中可以看出，gc2355的Init函数地址传给了pfFunc，也就是时候，后面在通用驱动可以直接 凭借pfun
指针调用sensorlist中的驱动
4.2 再来看ioctl(m_fdSensor, KDIMGSENSORIOC_T_CHECK_IS_ALIVE);

当KDIMGSENSORIOC_T_CHECK_IS_ALIVE被传下时，会调用kernel层的adopt_CAMERA_HW_Feature

Control接口

<code class=" hljs " style="border-radius: 3px; padding: 0.5em; font-family: Monaco, Menlo, Consolas, 'Courier New', monospace; font-size: 12px; color: rgb(248, 248, 242); border: 0px; display: block; overflow-x: auto; background: rgb(35, 36, 31);"><span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">static</span> <span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">inline</span> <span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">int</span> adopt_CAMERA_HW_CheckIsAlive(<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">void</span>)
{....<span class="hljs-comment" style="border-radius: 0px !important; color: rgb(117, 113, 94);">/* power on sensor */</span>kdModulePowerOn((CAMERA_DUAL_CAMERA_SENSOR_ENUM *) g_invokeSocketIdx, g_invokeSensorNameStr,<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">true</span>, CAMERA_HW_DRVNAME1);....<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">if</span> (g_pSensorFunc) {<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">for</span> (i = KDIMGSENSOR_INVOKE_DRIVER_0; i < KDIMGSENSOR_MAX_INVOKE_DRIVERS; i++) {<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">if</span> (DUAL_CAMERA_NONE_SENSOR != g_invokeSocketIdx[i]) {err =g_pSensorFunc->SensorFeatureControl(g_invokeSocketIdx[i],SENSOR_FEATURE_CHECK_SENSOR_ID,(MUINT8 *) &sensorID,&retLen);<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">if</span> (sensorID == <span class="hljs-number" style="border-radius: 0px !important; color: rgb(174, 129, 255);">0</span>) {	<span class="hljs-comment" style="border-radius: 0px !important; color: rgb(117, 113, 94);">/* not implement this feature ID */</span>PK_DBG(<span class="hljs-string" style="border-radius: 0px !important; color: rgb(230, 219, 116);">" Not implement!!, use old open function to check\n"</span>);err = ERROR_SENSOR_CONNECT_FAIL;} <span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">else</span> <span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">if</span> (sensorID == <span class="hljs-number" style="border-radius: 0px !important; color: rgb(174, 129, 255);">0xFFFFFFFF</span>) {	<span class="hljs-comment" style="border-radius: 0px !important; color: rgb(117, 113, 94);">/* fail to open the sensor */</span>PK_DBG(<span class="hljs-string" style="border-radius: 0px !important; color: rgb(230, 219, 116);">" No Sensor Found"</span>);err = ERROR_SENSOR_CONNECT_FAIL;} <span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">else</span> {PK_INF(<span class="hljs-string" style="border-radius: 0px !important; color: rgb(230, 219, 116);">" Sensor found ID = 0x%x\n"</span>, sensorID);<span class="hljs-built_in" style="border-radius: 0px !important; color: rgb(230, 219, 116);">snprintf</span>(mtk_ccm_name, <span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">sizeof</span>(mtk_ccm_name),<span class="hljs-string" style="border-radius: 0px !important; color: rgb(230, 219, 116);">"%s CAM[%d]:%s;"</span>, mtk_ccm_name,g_invokeSocketIdx[i], g_invokeSensorNameStr[i]);psensorResolution[<span class="hljs-number" style="border-radius: 0px !important; color: rgb(174, 129, 255);">0</span>] = &sensorResolution[<span class="hljs-number" style="border-radius: 0px !important; color: rgb(174, 129, 255);">0</span>];psensorResolution[<span class="hljs-number" style="border-radius: 0px !important; color: rgb(174, 129, 255);">1</span>] = &sensorResolution[<span class="hljs-number" style="border-radius: 0px !important; color: rgb(174, 129, 255);">1</span>];<span class="hljs-comment" style="border-radius: 0px !important; color: rgb(117, 113, 94);">// don't care of the result</span>g_pSensorFunc->SensorGetResolution(psensorResolution);<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">if</span>(g_invokeSocketIdx[i] == DUAL_CAMERA_MAIN_SENSOR)curr_sensor_id = <span class="hljs-number" style="border-radius: 0px !important; color: rgb(174, 129, 255);">0</span>;<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">else</span> <span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">if</span>(g_invokeSocketIdx[i] == DUAL_CAMERA_SUB_SENSOR)curr_sensor_id = <span class="hljs-number" style="border-radius: 0px !important; color: rgb(174, 129, 255);">1</span>;<span class="hljs-comment" style="border-radius: 0px !important; color: rgb(117, 113, 94);">/* fill the cam infos with name/width/height */</span><span class="hljs-built_in" style="border-radius: 0px !important; color: rgb(230, 219, 116);">snprintf</span>(g_cam_infos, <span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">sizeof</span>(g_cam_infos),<span class="hljs-string" style="border-radius: 0px !important; color: rgb(230, 219, 116);">"%s CAM[%d]:%s,Width:%d, Height:%d;"</span>,g_cam_infos, g_invokeSocketIdx[i], g_invokeSensorNameStr[i],sensorResolution[curr_sensor_id].SensorFullWidth, sensorResolution[curr_sensor_id].SensorFullHeight);err = ERROR_NONE;}<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">if</span> (ERROR_NONE != err) {PK_DBG(<span class="hljs-string" style="border-radius: 0px !important; color: rgb(230, 219, 116);">"ERROR:adopt_CAMERA_HW_CheckIsAlive(), No imgsensor alive\n"</span>);}}}} <span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">else</span> {PK_DBG(<span class="hljs-string" style="border-radius: 0px !important; color: rgb(230, 219, 116);">"ERROR:NULL g_pSensorFunc\n"</span>);}
}				<span class="hljs-comment" style="border-radius: 0px !important; color: rgb(117, 113, 94);">/* adopt_CAMERA_HW_Open() */</span></code>

这个函数非常重要，它主要进行了以下几个动作，
1）通过kdModulePowerOn给Sensor上电
2）通过SensorFeatureControl读取SensorID 
先看kdModulePowerOn的实现

<code class=" hljs " style="border-radius: 3px; padding: 0.5em; font-family: Monaco, Menlo, Consolas, 'Courier New', monospace; font-size: 12px; color: rgb(248, 248, 242); border: 0px; display: block; overflow-x: auto; background: rgb(35, 36, 31);"><span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">int</span>
kdModulePowerOn(CAMERA_DUAL_CAMERA_SENSOR_ENUM socketIdx[KDIMGSENSOR_MAX_INVOKE_DRIVERS],<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">char</span> sensorNameStr[KDIMGSENSOR_MAX_INVOKE_DRIVERS][<span class="hljs-number" style="border-radius: 0px !important; color: rgb(174, 129, 255);">32</span>], BOOL On, <span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">char</span> *mode_name)
{MINT32 ret = ERROR_NONE;u32 i = <span class="hljs-number" style="border-radius: 0px !important; color: rgb(174, 129, 255);">0</span>;<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">for</span> (i = KDIMGSENSOR_INVOKE_DRIVER_0; i < KDIMGSENSOR_MAX_INVOKE_DRIVERS; i++) {<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">if</span> (g_bEnableDriver[i]) {<span class="hljs-comment" style="border-radius: 0px !important; color: rgb(117, 113, 94);">/* PK_XLOG_INFO("[%s][%d][%d][%s][%s]\r\n",__FUNCTION__,g_bEnableDriver[i],socketIdx[i],sensorNameStr[i],mode_name); */</span>
<span class="hljs-preprocessor" style="border-radius: 0px !important;">#ifndef CONFIG_FPGA_EARLY_PORTING</span>ret = _kdCISModulePowerOn(socketIdx[i], sensorNameStr[i], On, mode_name);
<span class="hljs-preprocessor" style="border-radius: 0px !important;">#endif</span><span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">if</span> (ERROR_NONE != ret) {PK_ERR(<span class="hljs-string" style="border-radius: 0px !important; color: rgb(230, 219, 116);">"[%s]"</span>, __func__);<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">return</span> ret;}}}<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">return</span> ERROR_NONE;
}</code>

在kdModulePowerOn中又调用_kdCISModulePowerOn

<code class=" hljs " style="border-radius: 3px; padding: 0.5em; font-family: Monaco, Menlo, Consolas, 'Courier New', monospace; font-size: 12px; color: rgb(248, 248, 242); border: 0px; display: block; overflow-x: auto; background: rgb(35, 36, 31);"><span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">int</span> _kdCISModulePowerOn(CAMERA_DUAL_CAMERA_SENSOR_ENUM SensorIdx, <span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">char</span> *currSensorName, BOOL On,<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">char</span> *mode_name)
{....ret = kdCISModulePowerOn(SensorIdx, currSensorName, On, mode_name);....<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">return</span> ret;
}</code>

在_kdCISModulePowerOn又调用kdCISModulePowerOn函数
文件：kernel-3.18/drivers/misc/mediatek/imgsensor/src/mt6580/camera_hw/kd_camera_hw.c
//改函数为上下电函数，通过传入BOOL值来判断上/下电

<code class=" hljs " style="border-radius: 3px; padding: 0.5em; font-family: Monaco, Menlo, Consolas, 'Courier New', monospace; font-size: 12px; color: rgb(248, 248, 242); border: 0px; display: block; overflow-x: auto; background: rgb(35, 36, 31);"><span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">int</span> kdCISModulePowerOn(CAMERA_DUAL_CAMERA_SENSOR_ENUM SensorIdx, <span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">char</span> *currSensorName, BOOL On,<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">char</span> *mode_name)
{u32 pinSetIdx = <span class="hljs-number" style="border-radius: 0px !important; color: rgb(174, 129, 255);">0</span>;	<span class="hljs-comment" style="border-radius: 0px !important; color: rgb(117, 113, 94);">/* default main sensor */</span><span class="hljs-preprocessor" style="border-radius: 0px !important;">#define IDX_PS_CMRST 0</span>
<span class="hljs-preprocessor" style="border-radius: 0px !important;">#define IDX_PS_CMPDN 4</span>
<span class="hljs-preprocessor" style="border-radius: 0px !important;">#define IDX_PS_MODE 1</span>
<span class="hljs-preprocessor" style="border-radius: 0px !important;">#define IDX_PS_ON   2</span>
<span class="hljs-preprocessor" style="border-radius: 0px !important;">#define IDX_PS_OFF  3</span>
<span class="hljs-preprocessor" style="border-radius: 0px !important;">#define VOL_2800 2800000</span>
<span class="hljs-preprocessor" style="border-radius: 0px !important;">#define VOL_1800 1800000</span>
<span class="hljs-preprocessor" style="border-radius: 0px !important;">#define VOL_1500 1500000</span>
<span class="hljs-preprocessor" style="border-radius: 0px !important;">#define VOL_1200 1200000</span>
<span class="hljs-preprocessor" style="border-radius: 0px !important;">#define VOL_1000 1000000</span>u32 pinSet[<span class="hljs-number" style="border-radius: 0px !important; color: rgb(174, 129, 255);">3</span>][<span class="hljs-number" style="border-radius: 0px !important; color: rgb(174, 129, 255);">8</span>] = {<span class="hljs-comment" style="border-radius: 0px !important; color: rgb(117, 113, 94);">/* for main sensor */</span>{		<span class="hljs-comment" style="border-radius: 0px !important; color: rgb(117, 113, 94);">/* The reset pin of main sensor uses GPIO10 of mt6306, please call mt6306 API to set */</span>CAMERA_CMRST_PIN,CAMERA_CMRST_PIN_M_GPIO,	<span class="hljs-comment" style="border-radius: 0px !important; color: rgb(117, 113, 94);">/* mode */</span>GPIO_OUT_ONE,	<span class="hljs-comment" style="border-radius: 0px !important; color: rgb(117, 113, 94);">/* ON state */</span>GPIO_OUT_ZERO,	<span class="hljs-comment" style="border-radius: 0px !important; color: rgb(117, 113, 94);">/* OFF state */</span>CAMERA_CMPDN_PIN,CAMERA_CMPDN_PIN_M_GPIO,GPIO_OUT_ONE,GPIO_OUT_ZERO,},<span class="hljs-comment" style="border-radius: 0px !important; color: rgb(117, 113, 94);">/* for sub sensor */</span>{CAMERA_CMRST1_PIN,CAMERA_CMRST1_PIN_M_GPIO,GPIO_OUT_ONE,GPIO_OUT_ZERO,CAMERA_CMPDN1_PIN,CAMERA_CMPDN1_PIN_M_GPIO,GPIO_OUT_ONE,GPIO_OUT_ZERO,},<span class="hljs-comment" style="border-radius: 0px !important; color: rgb(117, 113, 94);">/* for main_2 sensor */</span>{GPIO_CAMERA_INVALID,GPIO_CAMERA_INVALID,	<span class="hljs-comment" style="border-radius: 0px !important; color: rgb(117, 113, 94);">/* mode */</span>GPIO_OUT_ONE,	<span class="hljs-comment" style="border-radius: 0px !important; color: rgb(117, 113, 94);">/* ON state */</span>GPIO_OUT_ZERO,	<span class="hljs-comment" style="border-radius: 0px !important; color: rgb(117, 113, 94);">/* OFF state */</span>GPIO_CAMERA_INVALID,GPIO_CAMERA_INVALID,GPIO_OUT_ONE,GPIO_OUT_ZERO,}};<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">if</span> (DUAL_CAMERA_MAIN_SENSOR == SensorIdx)pinSetIdx = <span class="hljs-number" style="border-radius: 0px !important; color: rgb(174, 129, 255);">0</span>;<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">else</span> <span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">if</span> (DUAL_CAMERA_SUB_SENSOR == SensorIdx)pinSetIdx = <span class="hljs-number" style="border-radius: 0px !important; color: rgb(174, 129, 255);">1</span>;<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">else</span> <span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">if</span> (DUAL_CAMERA_MAIN_2_SENSOR == SensorIdx)pinSetIdx = <span class="hljs-number" style="border-radius: 0px !important; color: rgb(174, 129, 255);">2</span>;<span class="hljs-comment" style="border-radius: 0px !important; color: rgb(117, 113, 94);">/* power ON */</span><span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">if</span> (On) {<span class="hljs-preprocessor" style="border-radius: 0px !important;">#if 0</span>ISP_MCLK1_EN(<span class="hljs-number" style="border-radius: 0px !important; color: rgb(174, 129, 255);">1</span>);ISP_MCLK2_EN(<span class="hljs-number" style="border-radius: 0px !important; color: rgb(174, 129, 255);">1</span>);ISP_MCLK3_EN(<span class="hljs-number" style="border-radius: 0px !important; color: rgb(174, 129, 255);">1</span>);
<span class="hljs-preprocessor" style="border-radius: 0px !important;">#else</span><span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">if</span> (pinSetIdx == <span class="hljs-number" style="border-radius: 0px !important; color: rgb(174, 129, 255);">0</span>)ISP_MCLK1_EN(<span class="hljs-number" style="border-radius: 0px !important; color: rgb(174, 129, 255);">1</span>);<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">else</span> <span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">if</span> (pinSetIdx == <span class="hljs-number" style="border-radius: 0px !important; color: rgb(174, 129, 255);">1</span>)ISP_MCLK2_EN(<span class="hljs-number" style="border-radius: 0px !important; color: rgb(174, 129, 255);">1</span>);
<span class="hljs-preprocessor" style="border-radius: 0px !important;">#endif</span>printk(<span class="hljs-string" style="border-radius: 0px !important; color: rgb(230, 219, 116);">"fangkuiccm %d ,currSensorName = %s pinSetIdx = %d "</span>,__LINE__,currSensorName,pinSetIdx );<span class="hljs-comment" style="border-radius: 0px !important; color: rgb(117, 113, 94);">//通过DriverName来区分SensorIC</span><span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">if</span> (currSensorName && (<span class="hljs-number" style="border-radius: 0px !important; color: rgb(174, 129, 255);">0</span> == <span class="hljs-built_in" style="border-radius: 0px !important; color: rgb(230, 219, 116);">strcmp</span>(SENSOR_DRVNAME_GC2355_MIPI_RAW, currSensorName))) {<span class="hljs-comment" style="border-radius: 0px !important; color: rgb(117, 113, 94);">/* First Power Pin low and Reset Pin Low */</span><span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">if</span> (GPIO_CAMERA_INVALID != pinSet[pinSetIdx][IDX_PS_CMPDN])mtkcam_gpio_set(pinSetIdx, CAMPDN,pinSet[pinSetIdx][IDX_PS_CMPDN + IDX_PS_OFF]);<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">if</span> (GPIO_CAMERA_INVALID != pinSet[pinSetIdx][IDX_PS_CMRST])mtkcam_gpio_set(pinSetIdx, CAMRST,pinSet[pinSetIdx][IDX_PS_CMRST + IDX_PS_OFF]);mdelay(<span class="hljs-number" style="border-radius: 0px !important; color: rgb(174, 129, 255);">50</span>);<span class="hljs-comment" style="border-radius: 0px !important; color: rgb(117, 113, 94);">/* VCAM_A */</span><span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">if</span> (TRUE != _hwPowerOn(VCAMA, VOL_2800)) {PK_DBG(<span class="hljs-string" style="border-radius: 0px !important; color: rgb(230, 219, 116);">"[CAMERA SENSOR] Fail to enable analog power (VCAM_A),power id = %d\n"</span>,VCAMA);<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">goto</span> _kdCISModulePowerOn_exit_;}mdelay(<span class="hljs-number" style="border-radius: 0px !important; color: rgb(174, 129, 255);">10</span>);<span class="hljs-comment" style="border-radius: 0px !important; color: rgb(117, 113, 94);">/* VCAM_IO */</span><span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">if</span> (TRUE != _hwPowerOn(VCAMIO, VOL_1800)) {PK_DBG(<span class="hljs-string" style="border-radius: 0px !important; color: rgb(230, 219, 116);">"[CAMERA SENSOR] Fail to enable IO power (VCAM_IO),power id = %d\n"</span>,VCAMIO);<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">goto</span> _kdCISModulePowerOn_exit_;}mdelay(<span class="hljs-number" style="border-radius: 0px !important; color: rgb(174, 129, 255);">10</span>);<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">if</span> (TRUE != _hwPowerOn(VCAMD, VOL_1500)) {PK_DBG(<span class="hljs-string" style="border-radius: 0px !important; color: rgb(230, 219, 116);">"[CAMERA SENSOR] Fail to enable digital power (VCAM_D),power id = %d\n"</span>,VCAMD);<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">goto</span> _kdCISModulePowerOn_exit_;}mdelay(<span class="hljs-number" style="border-radius: 0px !important; color: rgb(174, 129, 255);">10</span>);<span class="hljs-comment" style="border-radius: 0px !important; color: rgb(117, 113, 94);">/* AF_VCC */</span><span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">if</span> (TRUE != _hwPowerOn(VCAMAF, VOL_2800)) {PK_DBG(<span class="hljs-string" style="border-radius: 0px !important; color: rgb(230, 219, 116);">"[CAMERA SENSOR] Fail to enable analog power (VCAM_AF),power id = %d\n"</span>,VCAMAF);<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">goto</span> _kdCISModulePowerOn_exit_;}mdelay(<span class="hljs-number" style="border-radius: 0px !important; color: rgb(174, 129, 255);">50</span>);<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">if</span> (GPIO_CAMERA_INVALID != pinSet[pinSetIdx][IDX_PS_CMRST]) {mtkcam_gpio_set(pinSetIdx, CAMRST,pinSet[pinSetIdx][IDX_PS_CMRST + IDX_PS_OFF]);mdelay(<span class="hljs-number" style="border-radius: 0px !important; color: rgb(174, 129, 255);">5</span>);mtkcam_gpio_set(pinSetIdx, CAMRST,pinSet[pinSetIdx][IDX_PS_CMRST + IDX_PS_ON]);}mdelay(<span class="hljs-number" style="border-radius: 0px !important; color: rgb(174, 129, 255);">5</span>);<span class="hljs-comment" style="border-radius: 0px !important; color: rgb(117, 113, 94);">/* enable active sensor */</span><span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">if</span> (GPIO_CAMERA_INVALID != pinSet[pinSetIdx][IDX_PS_CMPDN]) {mtkcam_gpio_set(pinSetIdx, CAMPDN,pinSet[pinSetIdx][IDX_PS_CMPDN + IDX_PS_ON]);mdelay(<span class="hljs-number" style="border-radius: 0px !important; color: rgb(174, 129, 255);">5</span>);mtkcam_gpio_set(pinSetIdx, CAMPDN,pinSet[pinSetIdx][IDX_PS_CMPDN + IDX_PS_OFF]);}mdelay(<span class="hljs-number" style="border-radius: 0px !important; color: rgb(174, 129, 255);">5</span>);} }<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">else</span>{ <span class="hljs-comment" style="border-radius: 0px !important; color: rgb(117, 113, 94);">//poweroff</span><span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">if</span> (currSensorName   <span class="hljs-comment" style="border-radius: 0px !important; color: rgb(117, 113, 94);">//上完电就要下电不然会造成漏电，最终会影响手机功耗</span>&& (<span class="hljs-number" style="border-radius: 0px !important; color: rgb(174, 129, 255);">0</span> == <span class="hljs-built_in" style="border-radius: 0px !important; color: rgb(230, 219, 116);">strcmp</span>(SENSOR_DRVNAME_GC2355_MIPI_RAW, currSensorName))) {
<span class="hljs-preprocessor" style="border-radius: 0px !important;">#if 0</span>mt_set_gpio_mode(GPIO_SPI_MOSI_PIN, GPIO_MODE_00);mt_set_gpio_dir(GPIO_SPI_MOSI_PIN, GPIO_DIR_OUT);mt_set_gpio_out(GPIO_SPI_MOSI_PIN, GPIO_OUT_ONE);
<span class="hljs-preprocessor" style="border-radius: 0px !important;">#endif</span><span class="hljs-comment" style="border-radius: 0px !important; color: rgb(117, 113, 94);">/* First Power Pin low and Reset Pin Low */</span><span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">if</span> (GPIO_CAMERA_INVALID != pinSet[pinSetIdx][IDX_PS_CMPDN]) {<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">if</span> (mt_set_gpio_mode(pinSet[pinSetIdx][IDX_PS_CMPDN],pinSet[pinSetIdx][IDX_PS_CMPDN + IDX_PS_MODE])) {PK_DBG(<span class="hljs-string" style="border-radius: 0px !important; color: rgb(230, 219, 116);">"[CAMERA LENS] set gpio mode failed!! (CMPDN)\n"</span>);}<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">if</span> (mt_set_gpio_dir(pinSet[pinSetIdx][IDX_PS_CMPDN], GPIO_DIR_OUT)) {PK_DBG(<span class="hljs-string" style="border-radius: 0px !important; color: rgb(230, 219, 116);">"[CAMERA LENS] set gpio dir failed!! (CMPDN)\n"</span>);}<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">if</span> (mt_set_gpio_out(pinSet[pinSetIdx][IDX_PS_CMPDN],pinSet[pinSetIdx][IDX_PS_CMPDN + IDX_PS_OFF])) {PK_DBG(<span class="hljs-string" style="border-radius: 0px !important; color: rgb(230, 219, 116);">"[CAMERA LENS] set gpio failed!! (CMPDN)\n"</span>);}}}
}</code>

上电操作完成后，紧接着读取SensorID，通用驱动使用SensorFeatureControl来读取ID如：
 g_pSensorFunc->SensorFeatureControl(g_invokeSocketIdx[i],
SENSOR_FEATURE_CHECK_SENSOR_ID,
(MUINT8 *) &sensorID,
&retLen);
这步操作会调用GC2355中的feature_control函数如下：
文件：kernel-3.18/drivers/misc/mediatek/imgsensor/src/mt6580/gc2355_mipi_raw/gc2355mipi_Sensor.c

<code class=" hljs " style="border-radius: 3px; padding: 0.5em; font-family: Monaco, Menlo, Consolas, 'Courier New', monospace; font-size: 12px; color: rgb(248, 248, 242); border: 0px; display: block; overflow-x: auto; background: rgb(35, 36, 31);"><span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">static</span> kal_uint32 feature_control(MSDK_SENSOR_FEATURE_ENUM feature_id,UINT8 *feature_para,UINT32 *feature_para_len)
{....LOG_INF(<span class="hljs-string" style="border-radius: 0px !important; color: rgb(230, 219, 116);">"feature_id = %d\n"</span>, feature_id);<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">switch</span> (feature_id) {....<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">case</span> SENSOR_FEATURE_CHECK_SENSOR_ID:get_imgsensor_id(feature_return_para_32);<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">break</span>;....<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">default</span>:<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">break</span>;}<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">return</span> ERROR_NONE;
}    </code>

优化传入的cmd为SENSOR_FEATURE_CHECK_SENSOR_ID，则会调用feature_control中的

get_imgsensor_id再看get_imgsensor_id的实现

<code class=" hljs " style="border-radius: 3px; padding: 0.5em; font-family: Monaco, Menlo, Consolas, 'Courier New', monospace; font-size: 12px; color: rgb(248, 248, 242); border: 0px; display: block; overflow-x: auto; background: rgb(35, 36, 31);"><span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">static</span> kal_uint32 get_imgsensor_id(UINT32 *sensor_id)
{kal_uint8 i = <span class="hljs-number" style="border-radius: 0px !important; color: rgb(174, 129, 255);">0</span>;kal_uint8 retry = <span class="hljs-number" style="border-radius: 0px !important; color: rgb(174, 129, 255);">2</span>;<span class="hljs-comment" style="border-radius: 0px !important; color: rgb(117, 113, 94);">//sensor have two i2c address 0x6c 0x6d & 0x21 0x20, we should detect the module used i2c address</span><span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">while</span> (imgsensor_info.i2c_addr_table[i] != <span class="hljs-number" style="border-radius: 0px !important; color: rgb(174, 129, 255);">0xff</span>) {spin_lock(&imgsensor_drv_lock);imgsensor.i2c_write_id = imgsensor_info.i2c_addr_table[i];spin_unlock(&imgsensor_drv_lock);<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">do</span> {*sensor_id = return_sensor_id(); <span class="hljs-comment" style="border-radius: 0px !important; color: rgb(117, 113, 94);">//return_sensor_id读取IC的ID</span><span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">if</span> (*sensor_id == imgsensor_info.sensor_id) {LOG_INF(<span class="hljs-string" style="border-radius: 0px !important; color: rgb(230, 219, 116);">"i2c write id: 0x%x, sensor id: 0x%x\n"</span>, imgsensor.i2c_write_id,*sensor_id);<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">return</span> ERROR_NONE;}LOG_INF(<span class="hljs-string" style="border-radius: 0px !important; color: rgb(230, 219, 116);">"Read sensor id fail, write id: 0x%x, id: 0x%x\n"</span>, imgsensor.i2c_write_id,*sensor_id);retry--;} <span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">while</span>(retry > <span class="hljs-number" style="border-radius: 0px !important; color: rgb(174, 129, 255);">0</span>);i++;retry = <span class="hljs-number" style="border-radius: 0px !important; color: rgb(174, 129, 255);">2</span>;}....<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">return</span> ERROR_NONE;
}</code>

再看return_sensor_id的实现

<code class=" hljs " style="border-radius: 3px; padding: 0.5em; font-family: Monaco, Menlo, Consolas, 'Courier New', monospace; font-size: 12px; color: rgb(248, 248, 242); border: 0px; display: block; overflow-x: auto; background: rgb(35, 36, 31);"><span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">static</span> kal_uint32 return_sensor_id(<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">void</span>)
{<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">return</span> ((read_cmos_sensor(<span class="hljs-number" style="border-radius: 0px !important; color: rgb(174, 129, 255);">0xf0</span>) << <span class="hljs-number" style="border-radius: 0px !important; color: rgb(174, 129, 255);">8</span>) | read_cmos_sensor(<span class="hljs-number" style="border-radius: 0px !important; color: rgb(174, 129, 255);">0xf1</span>));
}
<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">static</span> kal_uint16 read_cmos_sensor(kal_uint32 addr)
{kal_uint16 get_byte=<span class="hljs-number" style="border-radius: 0px !important; color: rgb(174, 129, 255);">0</span>;<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">char</span> pu_send_cmd[<span class="hljs-number" style="border-radius: 0px !important; color: rgb(174, 129, 255);">1</span>] = {(<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">char</span>)(addr & <span class="hljs-number" style="border-radius: 0px !important; color: rgb(174, 129, 255);">0xFF</span>) };iReadRegI2C(pu_send_cmd, <span class="hljs-number" style="border-radius: 0px !important; color: rgb(174, 129, 255);">1</span>, (u8*)&get_byte, <span class="hljs-number" style="border-radius: 0px !important; color: rgb(174, 129, 255);">1</span>, imgsensor.i2c_write_id);<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">return</span> get_byte;}</code>

文件：kernel-3.18/drivers/misc/mediatek/imgsensor/src/mt6580/kd_sensorlist.c

<code class=" hljs " style="border-radius: 3px; padding: 0.5em; font-family: Monaco, Menlo, Consolas, 'Courier New', monospace; font-size: 12px; color: rgb(248, 248, 242); border: 0px; display: block; overflow-x: auto; background: rgb(35, 36, 31);"><span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">int</span> iReadRegI2C(u8 *a_pSendData, u16 a_sizeSendData, u8 *a_pRecvData, u16 a_sizeRecvData,u16 i2cId)
{<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">int</span> i4RetValue = <span class="hljs-number" style="border-radius: 0px !important; color: rgb(174, 129, 255);">0</span>;<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">if</span> (gI2CBusNum == SUPPORT_I2C_BUS_NUM1) {spin_lock(&kdsensor_drv_lock);g_pstI2Cclient->addr = (i2cId >> <span class="hljs-number" style="border-radius: 0px !important; color: rgb(174, 129, 255);">1</span>);g_pstI2Cclient->ext_flag = (g_pstI2Cclient->ext_flag) & (~I2C_DMA_FLAG);<span class="hljs-comment" style="border-radius: 0px !important; color: rgb(117, 113, 94);">/* Remove i2c ack error log during search sensor */</span><span class="hljs-comment" style="border-radius: 0px !important; color: rgb(117, 113, 94);">/* PK_ERR("g_pstI2Cclient->ext_flag: %d", g_IsSearchSensor); */</span><span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">if</span> (g_IsSearchSensor == <span class="hljs-number" style="border-radius: 0px !important; color: rgb(174, 129, 255);">1</span>) {g_pstI2Cclient->ext_flag = (g_pstI2Cclient->ext_flag) | I2C_A_FILTER_MSG;} <span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">else</span> {g_pstI2Cclient->ext_flag = (g_pstI2Cclient->ext_flag) & (~I2C_A_FILTER_MSG);}spin_unlock(&kdsensor_drv_lock);<span class="hljs-comment" style="border-radius: 0px !important; color: rgb(117, 113, 94);">/*  */</span>i4RetValue = i2c_master_send(g_pstI2Cclient, a_pSendData, a_sizeSendData);<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">if</span> (i4RetValue != a_sizeSendData) {PK_ERR(<span class="hljs-string" style="border-radius: 0px !important; color: rgb(230, 219, 116);">"[CAMERA SENSOR] I2C send failed!!, Addr = 0x%x\n"</span>, a_pSendData[<span class="hljs-number" style="border-radius: 0px !important; color: rgb(174, 129, 255);">0</span>]);<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">return</span> -<span class="hljs-number" style="border-radius: 0px !important; color: rgb(174, 129, 255);">1</span>;}i4RetValue = i2c_master_recv(g_pstI2Cclient, (<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">char</span> *)a_pRecvData, a_sizeRecvData);<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">if</span> (i4RetValue != a_sizeRecvData) {PK_ERR(<span class="hljs-string" style="border-radius: 0px !important; color: rgb(230, 219, 116);">"[CAMERA SENSOR] I2C read failed!!\n"</span>);<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">return</span> -<span class="hljs-number" style="border-radius: 0px !important; color: rgb(174, 129, 255);">1</span>;}} <span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">else</span> {spin_lock(&kdsensor_drv_lock);g_pstI2Cclient2->addr = (i2cId >> <span class="hljs-number" style="border-radius: 0px !important; color: rgb(174, 129, 255);">1</span>);<span class="hljs-comment" style="border-radius: 0px !important; color: rgb(117, 113, 94);">/* Remove i2c ack error log during search sensor */</span><span class="hljs-comment" style="border-radius: 0px !important; color: rgb(117, 113, 94);">/* PK_ERR("g_pstI2Cclient2->ext_flag: %d", g_IsSearchSensor); */</span><span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">if</span> (g_IsSearchSensor == <span class="hljs-number" style="border-radius: 0px !important; color: rgb(174, 129, 255);">1</span>) {g_pstI2Cclient2->ext_flag = (g_pstI2Cclient2->ext_flag) | I2C_A_FILTER_MSG;} <span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">else</span> {g_pstI2Cclient2->ext_flag = (g_pstI2Cclient2->ext_flag) & (~I2C_A_FILTER_MSG);}spin_unlock(&kdsensor_drv_lock);i4RetValue = i2c_master_send(g_pstI2Cclient2, a_pSendData, a_sizeSendData);<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">if</span> (i4RetValue != a_sizeSendData) {PK_ERR(<span class="hljs-string" style="border-radius: 0px !important; color: rgb(230, 219, 116);">"[CAMERA SENSOR] I2C send failed!!, Addr = 0x%x\n"</span>, a_pSendData[<span class="hljs-number" style="border-radius: 0px !important; color: rgb(174, 129, 255);">0</span>]);<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">return</span> -<span class="hljs-number" style="border-radius: 0px !important; color: rgb(174, 129, 255);">1</span>;}i4RetValue = i2c_master_recv(g_pstI2Cclient2, (<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">char</span> *)a_pRecvData, a_sizeRecvData);<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">if</span> (i4RetValue != a_sizeRecvData) {PK_ERR(<span class="hljs-string" style="border-radius: 0px !important; color: rgb(230, 219, 116);">"[CAMERA SENSOR] I2C read failed!!\n"</span>);<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">return</span> -<span class="hljs-number" style="border-radius: 0px !important; color: rgb(174, 129, 255);">1</span>;}}<span class="hljs-keyword" style="border-radius: 0px !important; color: rgb(249, 38, 114);">return</span> <span class="hljs-number" style="border-radius: 0px !important; color: rgb(174, 129, 255);">0</span>;
}</code>

   这一步完成I2c的读取，也就是说如果I2c配置正确，并且上电正确，到这一步就可以正确的读取ID，整

个camera也就基本就调通了。

三、总结

     通过上述分析，我们可以看出，camera驱动先是注册平台驱动，再注册I2c驱动，然后又为前后摄注册

字符设备，封装底层方法，上层访问底层驱动时候显示使用setdriver将具体IC的驱动入口获取，然后使用

checkisalive对sensorlist中的IC进行上电，上电完成就读取设备ID，到此为止，上层应用与底层驱动挂接

完成，紧接着就是预览和拍照，不过这都是具体IC驱动的实现了。